The present invention relates broadly to vaccines and more particularly relates to a dental vaccine for preventing or at least inhibiting periodontitis.
In this specification, the term periodontitis denotes a wide variety of diseases of humans and animals, which occur in the periodontal area of the oral cavity such as, for example, gingiva (gum), cementum and alveolar bone. It may in general be classified into the marginal periodontitis exemplified by pyorrhoea alveolaris and the apical periodontitis. Various known etiological factors of periodontitis include biological activities of virulent bacilli in the oral floras, such as, for example, the formation of dental plaque on the surface of teeth and the formation of cyst in the periodontal tissues, which breaks down the periodontal tissue. Such virulent oral bacilli are exemplified by Actinomyces viscosus, Actinomyces naeslundii, Bacteroides gingivalus, Actinobacillu actinomycetemcomitans and the like. Among them, Actinomyces viscosus is most important because this microorganism produces from sucrose a large amount of levan-type polysaccharides which greatly adhere to the surface of teeth. Although the periodontitis-inducing activities of other virulent bacilli are not necessarily stronger than the activity of Actinomyces viscosus, it is sometimes observed in practice that these microorganisms are capable of deteriorating periodontitis in coexistence with Actinomyces viscosus. Also, it is often found that the above-mentioned oral bacilli form a majority of the oral bacilli present in the focus of periodontitis.
Various proposals have hitherto been made to treat human periodontitis. However, to our knowledge, no vaccine for treating periodontitis is known in the art. On the other hand, it was previously known that, for example, the above-mentioned periodontitis-inducing oral bacilli possess the pili (fimbriae) on their cell surfaces, by the action of which they are capable of adhering (infecting) to the surfaces of teeth and/or the mucous membrane in the oral cavity. However, the antigenic characteristics of the pili of such virulent oral bacilli have not yet been clarified in view of etiological factors of periodontitis.
It has now unexpectedly been discovered that an antigen isolated from the pili of a periodontitis-inducing microorganism is capable of preventing or at least inhibiting the adherence (infection) of the microorganisms of at least same species to the surfaces of teeth and/or mucous membrane in an oral cavity.